603 
1907-8.] Middle Cells of Grey Matter of Spinal Cord. 
D 2. — See fig. 5. — Anterior cells, sometimes in small groups, but usually 
scattered. On the whole, larger than the others, but cannot be definitely 
separated from the central middle cells either by this or by another feature 
which helps to distinguish them, viz. the fact that they are often elongated 
along one axis. The long axis may have any orientation. The other middle 
cells may be scattered thickly or thinly, but often small, but not very com- 
pact, groups of from 6 to 18 cells are seen. Groups, when traced through 
two or three sections, often disappear or shift in position — there is no 
constancy. A central group is the most common, next most a post-central, 
Fig. 4. 
C 8—88 R ( x 32 ). 
a. An external central group of middle cells, extending between the 
motor groups. 
b. A few cells in the reticular area. 
c. Small para-central group. 
d. Central post-central group. 
A few small cells in area of Clarke’s column and anterior “scattered ” 
cells. 
on the outer side of and behind Clarke’s column. In the upper part more 
especially there are often cells in the reticular formation which, from their 
size, character, and casual occurrence, are probably not cells of the 
intermedio-lateral tract, but middle cells. In appearance and size, how- 
ever, the individual cells are very much alike. 
D 3. — Cells erratically distributed as usual, sometimes scattered, some- 
times in small groups. Chiefly polygonal, about the same size as those of 
the apical group of the intermedio-lateral tract, but staining rather more 
darkly ; others smaller, and rather more rounded in central and post-central 
areas. In base of anterior horn they are not markedly larger than else- 
